Focus On H1N1 Are We Ignoring H2N3?

Clinica is investigating the details and significance of Mexican health ministry statements that the H2N3 influenza virus was responsible for "the majority of cases tested" in an influenza outbreak in early April, three weeks before H1N1 came on the scene.

The existence of an additional strain of the disease raises fundamental questions concerning the management of the swine flu epidemic internationally.

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Comments made by Mexican health minister José Angel Córdova Villalobos during an April 27 press conference refer to the investigation of an outbreak reported in Perote, Veracruz, on April 2. The response on that day is said to have triggered a local alert and that "in looking for the influenza virus, the majority of cases tested were H2N3".

Clinica has not been able to ascertain from the health ministry the details behind these assertions, and awaits a response from the World Health Organization (WHO) to a request for feedback related to the presence or otherwise of H2N3 in Mexico, and the potential implications.

In terms of national pandemic control policies, the UK's Health Protection Agency said that its current screening of suspected cases is being targeted at detecting H1N1 and that, in not monitoring H2N3, the presence of this virus would not be revealed automatically.

What would be the implications of undiscovered H2N3 infection, such as in cleared suspected cases of H1N1? Would the co-presence of H2N3 fill in the ongoing gaps in our understanding of the new H1N1, such as Mexico's higher mortality rates? These are the kind of questions that may well enter the equation if H2N3 is involved.